If classical thermodynamics deals with macro states, why do we care how the heat transfer occurs? My understanding suggests that how the heat is transferred is irrelevant? All we care about are the final states of the systems after an equilibrium is reached? If we're not at equilibrium then we simply wait for equilibrium to occur. Why make the distinction?

If classical thermodynamics deals with macro states, why do we care how the heat transfer occurs? My understanding suggests that how the heat is transferred is irrelevant? All we care about are the final states of the systems after an equilibrium is reached? If we're not at equilibrium then we simply wait for equilibrium to occur. Why make the distinction?

 

Because some people use physics to design systems to do things. i.e. applied physics and engineering are real pursuits.

Thermodynamics theorizes equilibrium but is nicely misused outside any equilibrium as well...

 

Consider our atmosphere. Its "equilibrium" is not isothermal. It's a convective "equilibrium", where sunheat arrives much at the bottom and escapes much at the top. Thermodynamics permits us to compute the mean temperature gradient over the altitude.